For the first time in modern history a major Internet economy is being shut down. The Egyptian government appears to have cut off web and mobile phone access to much, if not most of its citizens ahead of a weekend of mass demonstrations against Hosni Mubarak. The country’s controversial president has been in power for nearly 30 years and local people are calling for regime change.

The country's key Internet Service Providers are also off the air, says James Cowie, the chief technology officer of Internet monitoring firm Renesys on his blog. “Virtually all of Egypt’s Internet addresses are now unreachable, worldwide.”

Another Internet monitoring firm, BGP Mon, says that 88% of the "Egyptian Internet" has been taken offline, according to its analysis. "Yesterday there were 2,903 Egyptian networks, originated from 52 ISP’s," researcher Andree Toonk says. Today there are only 327 Egyptian networks left.

How did this happen? Renesys observed an almost simultaneous withdrawal of all routes to Egyptian networks in the "Internet's global routing table" just after midnight, local time, last night: "Approximately 3,500 individual BGP [Border Gateway Protocol] routes were withdrawn, leaving no valid paths by which the rest of the world could continue to exchange internet traffic with Egypt's service providers."

All mobile operators in Egypt have been instructed to suspend services in selected areas. Under Egyptian legislation the authorities have the right to issue such an order and we are obliged to comply with it. The Egyptian authorities will be clarifying the situation in due course .

Activists have taken to Twitter to report on the situation while the local dialup network NOOR appears to still be online. One tweet that has been doing the rounds recommends that locals who have NOOR access or a working Wifi router remove their passwords in order to share access with neighbors.